Predictors of psychosocial functioning in euthymic patients with bipolar disorder: A model selection approach

Background: Functional impairment is a major target in the treatment of bipolar disorder (BD), but the magnitude and type of functional difficulties differ across patients. Findings on predictors of overall functioning and specific functional areas are inconsistent. We aimed to characterize functional difficulties and identify factors associated with global functioning and individual domains in euthymic patients. Methods: The Functional Assessment Short Test (FAST) was used to assess overall psychosocial functioning and specific functional domains in 80 euthymic participants with BD. Participants also completed a clinical interview and a cognitive assessment. Model selection with elastic net regression was performed to identify predictors of global functioning. We then examined the association of these predictors with individual functional domains using correlation. Results: FAST scores indicated moderate or severe impairment for 54% of the sample, with occupational functioning showing the highest impairment rate. Elastic net regression selected a model with three variables (higher residual depressive symptoms, lower executive functioning, more perceived cognitive deficits) as predictors of overall functioning. No significant associations were found between these predictors. Depressive symptoms were associated with interpersonal relationships and leisure time, executive skills with occupational functioning, and perceived deficits with cognitive functioning. Conclusions: Residual depressive symptoms were the strongest predictor of overall functioning which highlights the importance of assessing and targeting subthreshold symptoms for recovery. Executive difficulties were associated with functioning, particularly occupational skills, independently of depressive symptoms. Interventions targeting these difficulties, such as cognitive and functional remediation, may be key treatment options towards facilitating functional recovery.